The present invention relates to a method of transmitting an audio signal wherein an analog signal is converted to a digital signal, is coded, is digitally transmitted and reconverted to an analog signal, with the signal being converted before transmission into a digital signal representing the short-term spectrum, and portions of this signal which lie below given thresholds are left unconsidered on the basis of psycho-acoustic laws during coding of the digital signal to be transmitted.
Such a method is disclosed already in DE-OS No. 3,506,912. With the aid of this method, it is possible to keep the required transmission bandwidth small and manage with a narrowband channel, transmit as many audio signals as possible simultaneously over an existing channel or utilize an existing mass memory as economically as possible. This is based on the realization that, due to the psycho-acoustic characteristics of the human ear, a listener is unable to discern all components of a sound reproduction, i.e., some of these components are irrelevant in a data transmission sense. These components, which would take up a considerable portion of the otherwise required transmission capacity, are omitted.
It has been found that the decision as to which components may be omitted requires the consideration of various criteria separately or in combination with other criteria. If such consideration is not made, the omission of certain components may lead to unsatisfactory sound experiences in certain unusual sound events.